I. The Crystal Structures of Trimethyl Platinum Chloride and Tetramethyl Platinum. II. The Electron Diffraction Investigation of Dimethyl Sulfone, Dimethyl Sulfoxide, and Trimethyl Amine Oxide. III. The Heat Capacity and Entropy of Arsenic Trifluoride

Citation

Rundle, Robert Eugene (1941) I. The Crystal Structures of Trimethyl Platinum Chloride and Tetramethyl Platinum. II. The Electron Diffraction Investigation of Dimethyl Sulfone, Dimethyl Sulfoxide, and Trimethyl Amine Oxide. III. The Heat Capacity and Entropy of Arsenic Trifluoride. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/5ytm-8s13. https://resolver.caltech.edu/CaltechTHESIS:02232025-005122458

Abstract

All reported structures of tetravalent platinum compounds have involved octahedral coordination about platinum. Presumably, however, tetravalent platinum is capable of forming d²sp tetrahedral bonds, and the organo-platinum compounds, tetramethyl platinum and hexamethyl diplatinum, prepared by Gilman and Lichtenwalter were expected to have this configuration. In order to establish their structure and., if possible, to determine the tetrahedral radius of platinum, the X-ray study of these compounds was undertaken.

It early became necessary, however, to alter the plan of this research. Isolated tetrahedral molecules in the required number could not be packed into the observed unit cell of tetramethyl platinum. In addition the observed intensities, together with space group considerations, led to two non-equivalent sets of positions for the platinum atoms with identical structure factors. Finally, the scattering of the methyl groups was nearly negligible relative to ths.t of the platinum atoms. As a result neither chemical reasoning nor X-ray data permitted further progress. Fortunately some incomplete observations of Cox and Webster led to the discovery that trimethyl platinum chloride has a structure similar to that of tetramethyl platinum. In the structure of trimethyl platinum chloride the chlorine atoms could be located with some accuracy, and the platinum arrangement could be determined uniquely. This latter structure determination will therefore be discussed before the presentation of the results on tetramethyl platinum.

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